Hydraulic antifriction die set



Sepfiio 2% 119% a. Q. CONNER 2952339353 HYDRAULIC ANTIFRICTION DIE SET Filed Oct. 22, 1945 4 Sheets-Sheet l JIVVENTOR.

Sgpt. 26, 1950 G. o. CONNER ,3

HYDRAULIC ANTIFRICTION DIE SET Filed Oct. 22, 1945 4 Sheets-Sheet 2 INVENTOR. GUY O. CONNEIE Sept, 26, 1959 G. (I). CONNER HYDRAULIC ANTIFRICTION DIE SET 4 Sheets-Sheet 3 Filed Oct. 22, 1945- Patented Sept. 26, 1950 UNITED STATES PATENT OFFICE 12 Claims.

This invention relates to improvements in die sets and heads for punch presses or the like and more particularly to an improvement in means for maintaining alignment between the heads and/or die set parts \as well as the dies during punching or forming operations.

As is known to those versed in the art, a punch press usually includes a head which is movable relative to a base or bolster, which head and base carry dies and are effective to move the dies toward and from each other and perform forming or cutting operations on a material disposed therebetween. The accuracy of the forming or cutting effected by the dies is determined by the ability of the press to hold the dies in proper alignment with each other.

Heretofore it has been customary to provide so-called die sets for use in presses to maintain the desired alignment of the dies. In general, the die sets comprised separate plates or shoes carried by the head and bolster of the press respectively, and which plates are adapted to have mounted thereon the dies per se. It has also been common to provide pillars or posts usually known as leader pins that are rigidly secured in one of the plates and which extend toward and are reciprocable in bushings of guides carried by the other plate; the purpose being to maintain alignment of the plates and the dies carried thereby.

The accuracy of the alignment of the die parts during operation is largely determined by the fit of the leader pins in the bushings. If a loose fit is provided between the bushings and leader pins, there is more Opportunity for the plates to move laterally and for the dies to thus be carried out of alignment with each other. If attempts are made to decrease the tolerance or reduce this loose fit, the leader pins. and guides are apt to get hot and bind or seize, especially during high speed operation. As a matter of experience, at high speed operation, ordinary die sets have been known to get hot and seize in a few seconds time.

The importance of providing means for maintaining more exact alignment of the dies can be better appreciated by taking into consideration that the bolster and head of a press are normally massive devices, and in order to permit efiective operation, av clearance of between .002 and .005 inch must be provided between the working slides of the press. When it is further understood that the stock being worked holds them against lateral displacement relaon may be between .002 and .005 inch thick, it

will be seen that the tolerances or clearances necessary to the successful operation of the press are so large as to make it difficult, if not impractical, to operate on thin stock without the aid of die sets. This is especially true where a high speed operation is contemplated.

This deficiency is corrected somewhat by the use of the ordinary die set, since here the toleran-ce or clearance between the pins and the bushing may be cut down to .001 inch per inch of diameter of the pin. That is with a die set having leader pins one inch in diameter, the total clearance ma be .001 inch or a clearance on diametrically opposite sides of the pin of .0005 inch. However, it has been found that in operating on thin stock .002 inch thick the clearance between the cutting edge of the dies should not, :for best results, exceed 10 per cent of the stock thickness. Therefore, it appears that with .002 inch thickness stock, for best resuits the total clearance between the leader pins and bushings should not be over .0002 inch while there is actually .001 inch or five times as much clearance as is desirable. The result is that the dies are capable of greater lateral movement than. their clearance and the cutting edges are often actually riding on each other. This causes the cutting edges to be dulled and results in a shorter die life than would be possible if the dies could be kept in more perfect alignment.

One method and means for increasing the accuracy of the alignment of the dies and reducing the clearance between the leader pins and bushings is proposed in my copending application for Die, Set, Serial No. 519,284, now Patent No. 2,422,774 dated June 24, 1947. That application contemplates the useof anti-friction elements that may be of the rolling type, interposed under loaded conditions between the walls of the posts and the walls of the sockets.

The present invention contemplates providing the desired reduction. of the tolerance and/ or clearance by providing an improved support for the cooperating guiding members which includes utilizing a liquid film such as oil. The liquid oil film is interposed between the cooperating guiding members under pressure and The oil may be cooled if desired thus as- Fig. 1 is a vertical sectional view of a leader pin and a bushing with certain parts shown in elevation and with a portion of a die set shown attached thereto; I

Fig. 2 is a similar view of another modification of the invention;

Fig. 3 is a diagrammatic view illustrating my invention;

Fig. 4 is another diagrammatic view showing the invention as applied to a high speed press of my invention Fig. 5 is a fragmentary elevation of another embodiment of my invention with certain parts shown in section,

Fig. 6 is a sectional view on a reduced scale taken from a plane indicated by the line 6 of Fig. 5 of a complete die set of my invention.

Referring now to the drawings,-.throughout V which like parts are shown by like reference characters, and particularly to Fig. 1, there is illustrated at iii an upperlplate or shoe adapted to be secured to the traveling head or slide of the press. Secured in the upper plate iii, is a downwardly extending leader pin H which is cylindrical in form and provided with a smooth exterior surface. which may be secured to the bolster of the press and carries a guide for the leader pin which guide is secured in an aperture in the plate. The guid is in the form of a cylindrical sleeve [3 which is provided with a reduced portion !4 having a driven fit in the bore or aperture of the plate I2. A shoulder 45 on the sleeve engages with the upper surface of the plate l2. These parts are not of necessity cylindrical, but could be made square or of other shape if desired.

The cylinder I3 is provided with a sleeve it of alloy material such as silver, aluminum or copper and lead disposed in the guide and having a bore I! in alignment with the post I! and in which the post is adapted to reciprocate. bore I? is slightly larger than the post II, this dimension being exaggerated in the figures for the purpose of explanation. In actual practice the clearance could be varied but'is preferably kept relatively small, a clearance of .0005 per inch of diameter being satisfactory. The upper end of the sleeve is honed at 23 to provide a slight bell mouth. The upper end of the cylinder .is provided with an annular chamber H! which communicates exteriorly of the cylinder by a duct !9. The top of the cylinder is sealed around the post by a cap which is held on the cylinder by screws 2| that extend through the cap into threaded openings in the top of the cylinder. The ,cap is provided with a packing gland, illustrated generally at 22, which seals the top of the cylinder where the post ll enters the cylinder and prevents leakage of fluid, as will hereinafter be described, from the cylinder upwardly around the post. It may comprise an outer shell 25 carried by the cap 20 in the opening 26. A packing member 2! is disposed in a retaining ring 25 and held against the post II by .a split ring or spring 29. The member 27 may be of rubber, leather or other suitable material. Although a A lower plate 12 is provided.

The

specific type of packing gland is shown, it will N be appreciated that this is merely for the purpose of illustration and that other types could be substituted with equal facility as long as they prevent leakage of liquid around the post I l.

V 4 plate 32 which may be secured thereto in any suitable manner such as by studs 33. An outlet is provided in which a coupling 35 is disposed which connects to an outlet conduit 36.

The opposite faces l0 and I2 of the upper and lower plates ill and 12, respectively, are adapted to have secured thereto the usual die parts. There may be one or more of the posts and cylinder combinations as shown in Fig. 1 for each die set.

In operation a fluid such as oil is forced through the pipe 30 and duct I 9 into the chamber H3 at the top of the cylinder. This fluid then passes downward through the space between the leader pin and sleeve around the post ll into the lower part of the chamber [8 below the post ll. The fluid may escape from this chamber through the conduit 3'6 back to the pressure unit. The pressure unit may be a motor driven pump 3% (Fig. 3) supplying the fluid, which may be oil, under relatively high pressure.

The oil is kept constantly circulating during operation of the device and results in a high pressure resistance film of fluid between the post ii and the wall ll which holds the post firmly centered and limits lateral movement thereof. At the same time, the oil serves as a lubricant and is highly anti-friction in nature thus reducing the power needed to reciprocate the die set parts and maintaining extremely accurate alignment therebetween. The packing gland 22 prevents escape of the fluid around the entering portion of the post i I. The oil may be circulated through a cooling unit if desired to maintain the desired temperature thereof.

Fig. 2 is similar in operation to that just described. In this instance, however, the external pump may be eliminated and the film of oil maintained by a pumping action which is inherent in the construction shown.

As shown in the drawings the leader pin or post 4| is provided with an axial bore 42 extending throughout the length of the post, the upper end being closed by a threaded plug 43. It may be desirable in some instances to provide even greater space than is provided by the bore 42 without reducing the wall strength, in which instance the plug 43 would be removed and an auxiliary expansion chamber attached thereto. The chamber represented by the bore 42 may also be reduced in area if desired by providing an extension on the plug 43 as indicated bythe dotted lines at 43'.

The bore 42 extends axially downward through the post 4! opening through the bottom thereof. The cylinder 45, in this instance, is also secured in the plate I2 in a manner similar to'that described for the previous embodiment. It is provided with a bore 44 which has a relatively close fit with the post 4| as previously described in connection with the other embodiment. The lower part of the bore, however, is enlarged to provide an enlarged liquid holding chamber 46.

A packing gland 22' is provided at the top of the enlarged bore 46 surrounding the post 4|. The structure of the packing gland 22' has a bearing upon the operation in this case, since the member 2? acts as a valve allowing fluid to escape in a downward direction but prevents fluid fromescaping in an upward direction. The bottom of the chamber 46 is closed by a plate 41 which may be secured thereto in any suitable manner and in which a plug 48 is provided should it be desired to drain the same. The upper end of the cylinder 44 is closed by a cap 20' similar in construction to that described in the preceding embodiment except that the flange is threaded annular chamber 49 is provided adjacent the top of the cylinder and may be somewhat longer than thatshown in Fig. 1. A duct 50 may also be provided connected to a tube 5| for the purpose of the initial filling of the device. It is contemplated that the tube 5| be sealed ofl after the device is once filled or the opening may be plugged.

The post 4| is also provided with ducts 52 which extend through the sides of the post into the bore 42 approximately midway between the top and the bottom of the post. The position of these ducts may be varied depending upon the stroke of the press.

The bottom of the bore 42 in the post 4| is provided with a ball check valve 53 which is held seated on the seat 54 screwed in the bottom of the duct, by a spring 55.

In operation the device is filled with oil through the pipe 5| to approximately the level indicated at 60. This provides oil in the chamber 46, in the bore 42 up to the point 69 and between the walls of the cylinder at 44 and the post 4|. The chamber in the bore of the post above the level of the fluid at 60 is filled with air, which as previously stated could be increased in Volume by adding the auxiliary chamber at the top. This might be particularly desirable when the stroke of the press is increased.

In operation, the plates l and I2 being shown in the position where the dies are farthest apart,

when the two plates I0 and I2 are brought toway of ducts 52 and the space 44'. The packing gland 22 also acts as a valve in this instance causing the flow of liquid to always be in a downward direction and the reciprocation of the post 4| acts as a pump which provides a constant film of oil in the space at 44' holding the post and cylinder 43 and the plates Ill and I2 in proper alignment for most eflicient operation.

Fig. 4 is a diagrammatic view depicting the invention as applied to the die. carriers of the high speed press of my copending application, Serial No. 497,792, now Patent No. 2,406,808 dated September 3, 1946. In this case the upper die carrier is indicated at El and the lower carrier at 62, both mounted for movement in an orbital path toward and from each other on the eccentrics 63. The :posts correspond to the posts ll of Fig. 1 and the cylinder l3 also corresponds to the cylinders I3 of Fig. 1. In this case because the carriers both move, it is necessary to connect the inlets 30 to a hydraulic ball bearing joint 64 in order that those ducts may be flexibly connected to the outlet of a pump such as 39 of Fig. 3; Another hydraulic joint is indicated at 65, it being understood the object of these connections is. to connect the movable. die. sets to the pump, which is connected by couplings that permit relative movement therebetween. Like- Wise the outlets 36 are connected by similar couplings 66 shown to the inlet side of the pump. The operation otherwise is the same as that depicted for Figs. 1 and 3. Although I have shown Fig. 4 as being particularly adapted to utilize the specific invention of Fig. 1, it will be quite apparent that the device as shown in Fig. 2 could be used with this type of :press structure, and thatvin case the structure of Fig. 2 was used, that the connections and exterior pump would be unnecessary.

lt} will also be apparent that the hydraulic couplings would be replaced by flexible pressure resistance tubing in which joints such as 64, 65, and 66 would be unnecessary.

Inv Figs. 5 and 6, I have illustrated another modification of my invention, and wherein the leader pin may be rectangular in cross section and reciprocated between spaced plates which act as the guides.

More specifically, the upper plate In has secured therein in spaced relation to each other a pair of members 10. These members may be secured into or onto the plates in any suitable manner. As can best be seen in Fig. 6, these members are rectangular in cross section.

A third member H of similar shape is secured to the plat l2 and extends upward between the members 10 with its wallsin closely spaced relation to the opposing faces of the members it. It should be pointed out that for the purpose of clarity of description, the space between the member H and the members 10 is exaggerated, and that in actual practice, this space would be very small, being less than a thousandth of an inch.

The member H is provided with a duct 12 which communicates with a duct I3 in the plate l2, an inlet conduit 14 being connected thereto by a coupling 15. Branch ducts 16 connect with the duct 12 and open through the face of the member on opposite sides. These ducts comprise the means whereby fluid under pressure is admitted between the opposing faces of the member. If desired surface grooves, not shown, may be provided branching from the outlets of the ducts 16 to assist in the distribution of the fluid between the faces.

A 'fluid collection housing is provided at and comprises a shell of rectangular cross section which surrounds the members it and H, the lower end of the shell being secured in fluid tight relation by screws 8| which extend through a flange 32 and threaded into the plate I2. The upper end of' the shell is provided with rectangular openings 83, through which the members 70 mayreciprocate. The openings 83 surrounding the -members may be provided with packing glands 85' which prevent fluid from escaping around the members it and allow free reciprocation: thereof in the openings.

"One or more exhaust ducts 86 are providedv through the plate i2 andopening into the in-v terior: of. the shell being connected by the conduits 81 to. a suitable pump such as 39 of Fig. 3.

'As: shown in Fig. 6, four sets of the elements just described are provided, being disposed at thecorners: of the die set. It should be noted that the orientation: of the elements on the diagonally opposite corners are the same but that the elements on adjacent corners are rotated 90 degrees relative to each other. This arrangement provideslateral control of the plates I3 and |'2 in all directions.

In operation a fluid, such as. oil, is supplied to the ducts 12 by a pump 39 (Fig. 3) under pressure; the fluid escapes through the branch conduits 16' into the opposing faces of the members HI and H which provide a pressure resistant film between the faces holding the element 1 I midway between the elements 70.

The fluid under pressure gradually escapes from between the plates and is collected by the shell 80, being exhausted through the ducts 86 back to the pump 39. It may be desirable-to provide a fluid reservoir of substantial capacity ahead of the pump 39 on the inlet side; Insome instances, it may be desirable to have a separate pump for providing the exhaust and the pressure. a It will be appreciated that although I have shown the leader pins and guides as being cylindrical in cross section, they can be square or polygonal in cross section without departing from the spirit of my invention.

. It will thus be seen that'I have provided an invention wherein the lateral movement of the dies relative to each other is limited. The film of oil or other fluid used is suflicient, especially when the pressure providing the film is maintained, to rigidly hold the posts and cylinders It should be understood that although I have mentioned oil specifically as being the fluid used,

other fluids such as glycerine or metals in-the fluid state such as mercury could be used with equal facility. 7

Having thus described my invention, I am aware that numerous and extensive departures may be made therefrom without departing from the spirit or scope of the invention. I claim:

comprising posts carried by the upper plate and extending downwardin the direction of movement of the dies, cylinders carried by the lower plate and having said posts extending and reciprocable therein, a chamber at the top of each of said cylinders surrounding said post and inlet means connecting to said chamber, an outlet provided at the bottom of said chamber and means to force fluid under pressure into said upper chamber and-maintain a fluid film between said post and cylinder walls, and connected to said outlet duct to receive the fluid therefrom.

4.- A die set comprising upper andlower plates adapted to be secured in a press and to carry die parts, means to maintain alignment of said plates during pressing or punching operations comprising posts carried by one plate and extending in the direction of movement of the dies, cylinders carried by the other plate and having said posts extending and reciprocable therein, means for sealing said cylinder and post against fluid escape comprising a paclzinggland carried by the cylinder and surrounding said post adjacent the top thereof and surrounding said post and inlet means connecting to said chamber, an outlet provided at the bottom of said chamber and pump means connected to said inlets and outlets to force fluid under pressure into said upper chamber and maintain a fluid film between said post and cylinder walls.

5. A die set including an upper plate and a lower plate, posts carried by the upper plate and extending toward the lower plate, cylinders carried by the lower plate adapted to receive said posts, said cylinders each comprising an upper portion formed to provide a close sliding fit with said posts and formed with a chamber at the lower portion, said posts adapted to extend into r 1. An apparatus of the class described comprising upper and lower die supporting bases movable towardand :away from each other, means to maintain lateral alignment of said bases comprising a post carried by one base and extendsaid chamber, each post having a duct therein opening into said lower chamber thereof, said chamber being provided with a fluid, said post adapted to displace the fluid in said lower chamber and effective during reciprocation to pump said fluid between the walls of the posts and the cylinders and to maintain a film of fluid therebetween.

' 6. A die set comprising upper and lower plates, posts carried by the one of said plates and extending toward the other plate, cylinders carried by the last mentioned plate adapted to receive said posts, said cylinders each comprising an upper portioniormed 'toprovide a close sliding fit with said posts and a chamber at the lower and outlet ducts for said cylinder and means ing toward the other, a cylinder carried by the other plate for receiving said post, a film of oil under pressure disposed between the walls of the posts and cylinder and holding them out of contact with each other, and means to maintain said oil filmcomprising fluid inlet and outlet ducts for' said cylinder and means connected to said ducts to circulate oil under pressure therethrough.

portion, said posts adapted to extend into said chamber, each post having a duct extending axially ther'ethrough and communicating with said lower'chambe'r, a check valve in said duct, said'chamber'being provided with oil, said post adapted to displace the oil in said lower chamber and effective'during reciprocation to "pump said oil between the walls of the posts and the cylinders and'to maintain a film of-- oil therebetween. i '7. A die set comprising spaced members movable toward and from each other and adapted to carry dies, means to maintain lateral alignment between said members and dies comprising a post carried by one member and extendin toward the other member, a guide on said other member for receiving said post, said p'ostbeing provided with a :main duct extending. axially thereof a and opening'out of the. end remote from the supporting member, a check valve disposed in the end of the duct constituting-an inlet means for allowing fluid to be admitted to the duct and preventing fluid from es apingxthrough' the 'end of the duct,

outlet ducts extending from the first mentioned duct spaced from the end of the post; said guide including a portion for providin a close sliding fit with said post and having an annular chamber at its upper end, a reservoir at its lower end, a packing gland disposed at the upper end of said chamber and sealing said chamber around said post, said gland being arranged to prevent fluid flow out of said reservoir and admit fluid flow into said reservoir, said post and reservoir being filled with fluid to a point above said outlet ducts and the upper end of said main duct constituting an expansion and compression chamber for air or gas trapped above said fluid level, said post upon reciprocation adapted to move into said reservoir and displace fluid therefrom through said check valve and to compress the gas or air in the upper end of said main duct, said com pressed air or gas, upon the post being withdrawn from the chamber adapted to expand and force the fluid through the upper ducts into the annular chamber and downward between the walls of the post and cylinder to maintain a film of fluid under pressure therein.

8. An apparatus of the class described comprising spaced members movable toward and from each other and adapted to support forming elements, means for maintaining lateral alignment 'in all directions transversely to the direction of travel of said members comprising posts carried by one member and reciprocable between pairs "of posts carried by the other member said first posts and said pairs of posts having sides disposed in closely spaced relation and means to maintain a film of lubricating pressure resistant fluid in the spaces between said members.

9. An apparatus of the class described including spaced members adapted for movement toward and from each other and to support die parts, means to maintain lateral alignment of said members comprising a plate secured to one member and extending toward the other, a pair of plates carried by the other member adapted to receive said first plate therebetween, means for providing a fluid film between said plates, and a housing surrounding said plates for collecting fluid escaping from between the plates.

10. An apparatus of the class described comprising members movable toward and from each other and adapted to support die parts, guide means for maintaining said members in alignment comprising posts carried by one member and extending toward the other member and formed with a pair of oppositely disposed flat faces, pairs of posts carried by the. other members and having flat faces on each post facing each other, said first post adapted to reciprocate between said second posts, means including fluid ducts for said posts having outlet ports opening between said posts. and fluid pressure means for forcing a fluid under pressure between said posts, and means to collect fluid escaping from between said faces including a housing surrounding said posts.

11. An apparatus of the class described comprising members movable toward and away from each other and adapted to support die parts, means for maintaining said members against lateral movement in all directions transverse to the direction of travel thereof comprising cooperating guide means carried by the members, said guide means being disposed in spaced relation to each other and each comprising a plate of rectangular cross section carried by one member and extending toward the other and reciprocable in closely spaced relation between a pair of plates carried by the other member, fluid ducts formed in at least one of said plates and opening into the spaces between the plates, and means connected to said ducts for forcing fluid under pressure into the space between said plates, said members being provided with a plurality of sets of guide means with some of said guides oriented in one direction and others oriented at degrees thereto, and having means for said guide means to catch fluid expelled from between them.

12. A die set comprising spaced plates adapted for movement toward and from each other and to support die parts, guide means to hold said plates against lateral movement in all directions transverse to the direction of the travel comprising posts carried by one plate and extending toward the other, said posts having at least two opposite faces extending longitudinally thereof, said other plate being provided with a pair of spaced members adapted to reciprocably receive said posts therebetween and having faces disposed in closely spaced opposition to the faces in said post, said guide means being disposed in spaced relation from each other, said posts being formed with ducts therein and fluid outlet ports opening between said faces and means to force fluid into said ducts and provide a fluid film between said faces, and means encasing said guide means to receive fluid expelled from said faces and fluid outlet means for said encasing means to withdraw said fluid therefrom.

GUY O. CONNER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,729,898 Ruggles Oct. 1, 1929 1,921,421 Marsilius Aug. 8, 1933 2,288,136 Janiszewski June 30, 1942 

